Fuel shooting straight up from bowl vent on BJ-BK

[67428GT500]

I asked about the M6905 fuel pump and over-pressurization. The vehicle hadn't been ran much, but carbs were new, fuel pum, ect.
I pulled the carbs off twice and finally found the the issue of water penetration into the oil post two upper end tear downs with a small cyilnder wall crack on a 176 mile engine.  I had the hole sleeved and reassembled with new rings, bearings and gaskets.
However, I noted fuel shooting straight up via the vent tube. Should I be suspect of the pump or the needle valves.  It seems many here favor the Edelbrock offering, which is 145.00 pump after servicing the pump with the M6905 during rebuild.

I was curious what would be the wise choice here considering the information provided.

                                                                                                                -Keith

[Drew Pojedinec]

Use any pump ya want.  Just find a place to hide a regulator.
I like 4.5psi, but lotsa folks run more.
I find float control kinda hit or miss over 6psi.

Needles are always good to change.  If they are viton tipped needles, just buy a bag of 008 Orings and change them out.

[67428GT500]

There in lies the issue. Hard line 427 fuel filter / dual quad log. I have no idea how a regulator could be mounted/hidden. 

                                                                                                    -Keith

[Drew Pojedinec]

I get wanting to look original.  Sure, if it's a fancy original R code I'd totally do that.

Of course I have a general disrespect for numbers and prefer performance.  That said, I'd make the manual pump a dummy, install an electric like a Carter HP 4600 back by the tank and a regulator up near the engine bay, then run it through the dummy pump and into the factory hard piping.

If that seems like a lot of trouble, seek out smaller needle valves.  .097 handles higher pressure better than the typical .110 n&s that is common in every kit these days.  Worried about killing fuel flow?  don't.... you have four bowls to fill, there will be plenty of fuel.

[67428GT500]

Well, it's a real 1967 GT 500. So the OE look is important. I will change to the .097 window.  Quick fuel needles work, or Holley only?

[Drew Pojedinec]

They are all made in the same place.

[67428GT500]

I appreciate the advice, Drew.

                                            -Keith

[Barry_R]

....  If they are viton tipped needles, just buy a bag of 008 Orings and change them out.

The o-rings seem to be a big deal these days.  I find myself changing them out pretty often.  Current fuel hardens them up rather quickly and they leak.  I seem to remember that the original Holley stuff was a hair different than the common o-ring dimensions - fatter & did not dance around so much on the needle & seat.  I have the 8Rxxx engineering number around here somewhere, but do not have a drawing for comparison.

[blykins]

You don't know how many problems that I've had with these 2x4 setups and fuel pressure.  Regulators are a blessing.  Fuel pressure gauges that work are another blessing.

[67428GT500]

So did you figure out where to hide a regulator on a dual quad with the 427 fuel filter/hard line?

[blykins]

I just build the engines.....

What I'm saying is that if you build an engine big enough to need a big aftermarket fuel pump, you're gonna be faced with this scenario.  I've had at least 2 guys fire up an engine with a set of QFT 2x4 carbs and not understand that you can't run big fuel pressure.  It buries the needle into the seat and then floods out the vents. 

[machoneman]

....  If they are viton tipped needles, just buy a bag of 008 Orings and change them out.

The o-rings seem to be a big deal these days.  I find myself changing them out pretty often.  Current fuel hardens them up rather quickly and they leak.  I seem to remember that the original Holley stuff was a hair different than the common o-ring dimensions - fatter & did not dance around so much on the needle & seat.  I have the 8Rxxx engineering number around here somewhere, but do not have a drawing for comparison.

2X to what Barry said. Here in Chicago and with our 10% ethanol-laden gas (I do think this is the real culprit) the outer edge of the needle/seat o-rings not only hardens but shrinks the O.D. of the ring. Have had this happen on too many Holleys in the last few years to think it's coincidental.

Found out almost by accident. When pulling up and out a good O-ringed assembly, one can feel the drag imposed by the ring. Bad or hardened O-rings allow one to remove the assembly with little or no drag imposed by the fuel damaged O-ring. Btw, Holley and even Ace Hardware O-rings can and have had the same issues, again leading me to believe it is the gasoline!

What I wouldn't give for 100% pure Sunoco 260 at the pump again!

[FElony]

2X to what Barry said. Here in Chicago and with our 10% ethanol-laden gas (I do think this is the real culprit) the outer edge of the needle/seat o-rings not only hardens but shrinks the O.D. of the ring. Have had this happen on too many Holleys in the last few years to think it's coincidental.

Found out almost by accident. When pulling up and out a good O-ringed assembly, one can feel the drag imposed by the ring. Bad or hardened O-rings allow one to remove the assembly with little or no drag imposed by the fuel damaged O-ring. Btw, Holley and even Ace Hardware O-rings can and have had the same issues, again leading me to believe it is the gasoline!

What would be the pick for o-ring material here?   http://www.rubberstore.com/catalog/orings-c-33.html

[Drew Pojedinec]

What would be the pick for o-ring material here?   http://www.rubberstore.com/catalog/orings-c-33.html

IMG_1238 by Drew Pojedinec, on Flickr

I run McMaster-Carr part number 9464K13
I dunno how many I've really installed, but I've ordered a 100 pack 5 times, and I don't have that many on hand....  Haven't had an issue thus far.

[machoneman]

Believe FElony it's Viton material, just like the needle and seat tip mentioned here:

https://www.amazon.com/dp/B00DDQCG14/ref=psdc_15727521_t2_B00029JHGW

IIRC, nitrile material is the same or closest. I sized same at Ace with a good Holley ring and saved many bucks!